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TestDisk

Overview

TestDisk is a powerful open-source data recovery tool designed to recover lost or deleted partitions and repair corrupted filesystems. It can recover lost partitions, rebuild partition tables, and restore deleted files across multiple filesystem types. TestDisk is essential for digital forensics, disaster recovery, and data recovery operations in security assessments and incident response scenarios.

Installation

Debian/Ubuntu

sudo apt-get update
sudo apt-get install testdisk

macOS

brew install testdisk

From Source

wget https://www.cgsecurity.org/testdisk-7.1.tar.bz2
tar -xjf testdisk-7.1.tar.bz2
cd testdisk-7.1
./configure
make
sudo make install

Verify Installation

testdisk --version
testdisk --help

Core Components

ToolPurpose
testdiskPartition recovery and filesystem repair
photorecFile recovery from any storage media
fidentifyFile type identification

Basic TestDisk Usage

Interactive Mode

# Start interactive TestDisk
sudo testdisk

# Follow prompts to:
# 1. Select storage device
# 2. Choose partition table type
# 3. Analyze and recover partitions

Command-Line Mode

# List available disks
testdisk /list

# Analyze specific disk
sudo testdisk /dev/sda

# Verbose logging
sudo testdisk /debug /dev/sda

Device and Partition Selection

List Storage Devices

# List all block devices
lsblk

# List disks with TestDisk
testdisk /list

# Show detailed information
sudo fdisk -l

# List partitions
sudo parted -l

Select Target Device

# Specify device in TestDisk
testdisk /dev/sda

# For USB devices
testdisk /dev/sdb

# For NVMe drives
testdisk /dev/nvme0n1
DeviceType
/dev/sdaPrimary SATA drive
/dev/sdbSecondary SATA drive
/dev/nvme0n1NVMe SSD
/dev/sdcUSB device

Partition Table Analysis

Detect Partition Type

# Intel partition table (MBR)
# FAT, NTFS, ext2/3/4

# GUID Partition Table (GPT)
# Modern EFI systems

# Advanced partition scheme
# Multiple partition types

Analyze Partition Structure

# Quick search
# Scans partition headers

# Deep search
# Analyzes entire drive

# Ignore geometry errors
# For corrupted MBR

Partition Recovery Workflow

Interactive Recovery Process

# 1. Connect storage device
sudo testdisk

# 2. Select device from list
# Select /dev/sda

# 3. Choose partition table type
# Intel (MBR) or EFI (GPT)

# 4. Analyze partitions
# Auto or Manual

# 5. View found partitions
# Verify partition types

# 6. Write partition table
# Confirm recovery

Recovery Options

OptionFunction
Deeper SearchComprehensive scan
List FilesBrowse recovered files
BackupSave partition table
WriteRestore partition table

PhotoRec: File Recovery

Start PhotoRec

# Launch PhotoRec
sudo photorec

# Follow menu to:
# 1. Select storage device
# 2. Choose filesystem
# 3. Select file types
# 4. Run recovery

File Type Selection

# Common file types
# Images: JPG, PNG, GIF, RAW
# Documents: DOC, PDF, XLS
# Video: MP4, MOV, AVI
# Archives: ZIP, RAR, 7Z

Recover Specific File Types

# JPG images only
# Select JPG from list

# PDF documents
# Select PDF

# All file types
# Select "All" option

Recovery Parameters

ParameterPurpose
File FormatsSelect specific types
FilesystemTarget filesystem
Search PathRecovery location
BlocksizeSector size

Advanced Partition Operations

Backup Partition Table

# Create MBR backup
sudo dd if=/dev/sda of=mbr_backup.bin bs=512 count=1

# Create GPT backup
sudo sgdisk /dev/sda -b=gpt_backup.bin

# Export partition table
sudo testdisk /dev/sda /backup=sda.bak

Restore Partition Table

# Restore from backup
sudo dd if=mbr_backup.bin of=/dev/sda bs=512 count=1

# Restore GPT
sudo sgdisk /dev/sda -l=gpt_backup.bin

# Verify restoration
sudo parted -l

Filesystem Repair

Check Filesystem Integrity

# Check ext4 filesystem
sudo fsck -n /dev/sda1

# Check NTFS
sudo ntfsck /dev/sda1

# Check FAT32
sudo fsck.vfat /dev/sda1

Repair Corrupted Filesystem

# Ext4 repair
sudo fsck.ext4 -y /dev/sda1

# NTFS repair
sudo ntfsck -r /dev/sda1

# FAT32 repair
sudo fsck.vfat -y /dev/sda1

Mount Recovered Filesystem

# Create mount point
sudo mkdir -p /mnt/recovered

# Mount ext4
sudo mount -t ext4 /dev/sda1 /mnt/recovered

# Mount NTFS
sudo mount -t ntfs /dev/sda1 /mnt/recovered

# Mount FAT32
sudo mount -t vfat /dev/sda1 /mnt/recovered

Data Carving and Recovery

Carve Files from Raw Sectors

# Start file carving
sudo photorec

# Select device
# Select filesystem
# Choose output directory
# Select file types
# Run recovery

# Monitor progress
watch -n 1 'find recovered_files -type f | wc -l'

Targeted Recovery

# Recover images from range
# Specify sector range
# Set file type filters
# Run carving operation

# Example: Last 10GB only
# Set start/end sectors appropriately

Practical Workflow Examples

Recover Deleted Partition

# 1. Connect storage to recovery machine
# 2. Run TestDisk
sudo testdisk

# 3. Select device (e.g., /dev/sdb)
# 4. Choose partition type (Intel or EFI)
# 5. Run Deeper Search
# 6. Verify found partitions
# 7. Write partition table
# 8. Reboot system
# 9. Verify recovered partition
sudo parted -l

Restore Files from Deleted Partition

# 1. Run TestDisk or PhotoRec
sudo photorec

# 2. Select device
# 3. Choose target filesystem
# 4. Specify output directory
# 5. Select file types
# 6. Run recovery process

# 7. Monitor progress
# 8. Access recovered files
ls -la recovered_files/

Full System Recovery Procedure

# 1. Boot from recovery USB
# 2. Connect external drive
# 3. Analyze damaged drive
sudo testdisk /dev/sda

# 4. Recover partition table
# 5. Mount partitions
sudo mkdir -p /mnt/sda1
sudo mount /dev/sda1 /mnt/sda1

# 6. Extract critical data
rsync -av /mnt/sda1/ /external_drive/

# 7. Use PhotoRec for additional files
sudo photorec

Incident Response Data Preservation

# 1. Create forensic image
sudo dd if=/dev/sda of=forensic_image.dd bs=4M status=progress

# 2. Analyze image with TestDisk
testdisk /dev/loop0  # After loop mount

# 3. Recover deleted files
sudo photorec /dev/sda

# 4. Document findings
ls -la recovered_files/ > recovery_log.txt

Automation Scripts

Batch Recovery Script

#!/bin/bash
DEVICE=$1
OUTPUT_DIR="/mnt/recovery_$(date +%Y%m%d_%H%M%S)"

mkdir -p "$OUTPUT_DIR"

echo "[*] Starting recovery for $DEVICE"
echo "[*] Output: $OUTPUT_DIR"

# Run PhotoRec in batch mode
# Note: TestDisk/PhotoRec have limited CLI batch support
# Interactive mode is typically required

echo "[*] Mount device for manual recovery"
sudo mount "$DEVICE" "$OUTPUT_DIR"

Verify Recovery Results

#!/bin/bash
RECOVERY_DIR=$1

echo "[*] Recovery Statistics:"
echo "Total files: $(find "$RECOVERY_DIR" -type f | wc -l)"
echo "Total size: $(du -sh "$RECOVERY_DIR" | cut -f1)"

echo "[*] File type distribution:"
find "$RECOVERY_DIR" -type f | sed 's/.*\.//' | sort | uniq -c

echo "[*] Largest files:"
find "$RECOVERY_DIR" -type f -exec du -h {} + | sort -rh | head -10

Recovery Report Generator

#!/bin/bash
RECOVERY_DIR=$1
REPORT_FILE="recovery_report_$(date +%Y%m%d_%H%M%S).txt"

{
  echo "Recovery Report"
  echo "Generated: $(date)"
  echo "================================"
  echo ""
  echo "Statistics:"
  echo "Total Files: $(find "$RECOVERY_DIR" -type f | wc -l)"
  echo "Total Size: $(du -sh "$RECOVERY_DIR" | cut -f1)"
  echo ""
  echo "File Types:"
  find "$RECOVERY_DIR" -type f | sed 's/.*\.//' | sort | uniq -c
  echo ""
  echo "Largest Files:"
  find "$RECOVERY_DIR" -type f -exec du -h {} + | sort -rh | head -20
} > "$REPORT_FILE"

echo "[*] Report saved: $REPORT_FILE"

Forensic Best Practices

Preserve Original Media

# Create forensic image before recovery
sudo dd if=/dev/sda of=backup_image.dd bs=4M status=progress

# Verify image integrity
md5sum backup_image.dd > backup_image.md5
md5sum -c backup_image.md5

Document Recovery Process

# Log all commands
script -a recovery_session.log

# Record device information
sudo fdisk -l > device_info.txt
sudo parted -l >> device_info.txt

# Document findings
date > recovery_notes.txt
echo "Recovery performed on $(date)" >> recovery_notes.txt

Chain of Custody

# Hash original storage device
sudo md5sum /dev/sda > original_hash.txt

# Hash recovered data
find recovered_files -type f -exec md5sum {} + > recovered_hashes.txt

# Document all actions
echo "Recovery timestamp: $(date)" > chain_of_custody.log

Troubleshooting

Permission Denied Errors

# TestDisk requires root
sudo testdisk /dev/sda

# Or use sudo for all commands
sudo photorec

Device Not Recognized

# Check device detection
lsblk
sudo fdisk -l

# Reconnect device
# Try different USB port
# Check with dmesg
dmesg | tail -20

Recovery Takes Too Long

# Consider drive size vs free space
# Large drives take time
# Monitor progress
watch -n 10 'df -h'

# Can pause and resume
# Save recovery state

Corrupted Recovery Output

# Verify filesystem integrity
fsck -n /dev/sda1

# Try different recovery options
# Use Deeper Search
# Test different filesystem types

# Consider professional recovery if critical

Safety Considerations

Avoid Writing to Source Device

# Never write to source during recovery
# Mount read-only
sudo mount -r /dev/sda1 /mnt/

# Use external storage for recovery
# Verify target has space
df -h /target_directory

Backup Before Modifications

# Always backup original partition table
sudo sfdisk -d /dev/sda > partitions.bak

# Backup boot sector
sudo dd if=/dev/sda of=bootsector.bak bs=512 count=1

# Verify backup
ls -la *.bak
  • ddrescue — Data recovery with error handling
  • Autopsy — Digital forensics framework
  • Sleuth Kit — Forensic analysis toolkit
  • photorec — File carving (included with TestDisk)
  • fsck — Filesystem checking and repair